1 /* $OpenBSD: disksubr.c,v 1.10 2017/02/28 10:49:37 natano Exp $ */
2 /* $NetBSD: disksubr.c,v 1.21 1996/05/03 19:42:03 christos Exp $ */
3
4 /*
5 * Copyright (c) 1996 Theo de Raadt
6 * Copyright (c) 1982, 1986, 1988 Regents of the University of California.
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/buf.h>
37 #include <sys/disklabel.h>
38 #include <sys/disk.h>
39
40 /*
41 * Attempt to read a disk label from a device
42 * using the indicated strategy routine.
43 * The label must be partly set up before this:
44 * secpercyl, secsize and anything required for a block i/o read
45 * operation in the driver's strategy/start routines
46 * must be filled in before calling us.
47 *
48 * If dos partition table requested, attempt to load it and
49 * find disklabel inside a DOS partition.
50 *
51 * We would like to check if each MBR has a valid DOSMBR_SIGNATURE, but
52 * we cannot because it doesn't always exist. So.. we assume the
53 * MBR is valid.
54 */
55 int
readdisklabel(dev_t dev,void (* strat)(struct buf *),struct disklabel * lp,int spoofonly)56 readdisklabel(dev_t dev, void (*strat)(struct buf *),
57 struct disklabel *lp, int spoofonly)
58 {
59 struct buf *bp = NULL;
60 int error;
61
62 if ((error = initdisklabel(lp)))
63 goto done;
64
65 /* get a buffer and initialize it */
66 bp = geteblk(lp->d_secsize);
67 bp->b_dev = dev;
68
69 error = readdoslabel(bp, strat, lp, NULL, spoofonly);
70 if (error == 0)
71 goto done;
72
73 #if defined(CD9660)
74 error = iso_disklabelspoof(dev, strat, lp);
75 if (error == 0)
76 goto done;
77 #endif
78 #if defined(UDF)
79 error = udf_disklabelspoof(dev, strat, lp);
80 if (error == 0)
81 goto done;
82 #endif
83
84 done:
85 if (bp) {
86 bp->b_flags |= B_INVAL;
87 brelse(bp);
88 }
89 disk_change = 1;
90 return (error);
91 }
92
93 /*
94 * Write disk label back to device after modification.
95 */
96 int
writedisklabel(dev_t dev,void (* strat)(struct buf *),struct disklabel * lp)97 writedisklabel(dev_t dev, void (*strat)(struct buf *), struct disklabel *lp)
98 {
99 daddr_t partoff = -1;
100 int error = EIO;
101 int offset;
102 struct disklabel *dlp;
103 struct buf *bp = NULL;
104
105 /* get a buffer and initialize it */
106 bp = geteblk(lp->d_secsize);
107 bp->b_dev = dev;
108
109 if (readdoslabel(bp, strat, lp, &partoff, 1) != 0)
110 goto done;
111
112 /* Read it in, slap the new label in, and write it back out */
113 error = readdisksector(bp, strat, lp, DL_BLKTOSEC(lp, partoff +
114 DOS_LABELSECTOR));
115 if (error)
116 goto done;
117 offset = DL_BLKOFFSET(lp, partoff + DOS_LABELSECTOR);
118
119 dlp = (struct disklabel *)(bp->b_data + offset);
120 *dlp = *lp;
121 CLR(bp->b_flags, B_READ | B_WRITE | B_DONE);
122 SET(bp->b_flags, B_BUSY | B_WRITE | B_RAW);
123 (*strat)(bp);
124 error = biowait(bp);
125
126 done:
127 if (bp) {
128 bp->b_flags |= B_INVAL;
129 brelse(bp);
130 }
131 disk_change = 1;
132 return (error);
133 }
134